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Water and the Geelong Botanic Gardens
The Geelong Botanic Gardens have responded to drought conditions and water restrictions by looking for ways to minimise water use.
The 21st Century Garden is a dry landscape using minimal water and sustainable garden practices. The heritage part of the garden remains green due to an exemption which enables us to water important plant collections.
Water Restrictions and the Botanic Gardens
The City of Greater Geelong, along with the majority of the Barwon Region, progressed from Permanent Water Saving Restrictions in July 2006 to Stage 4 Water Restriction in December 2006.
The impact on the Botanic Gardens of the Stage 4 Restriction could have been extreme. Fortunately there are provisions in the Water Restrictions By-Law No. 187 and 189 to apply for an exemption to allow the use of potable (or mains water) for gardens open to the public.
The City of Greater Geelong applied for and was granted an exemption by Barwon Water to use potable water to sections of the Geelong Botanic Gardens to ensure the survival of this important historical garden which includes Heritage trees and scientific plant collections.
There are different requirements for water on the different sections of the garden depending on the species and layout of the garden bed.
The 21st Century Garden (opened in September 2002) has been developed with sustainable use of water in mind requiring very small volumes of water even in the driest times.
Other areas of the collection such as the 1851 Garden require more regular volumes of potable water particularly over the hotter summer months.
The impact of the past 10 years of drought has had a negative impact on many of the trees within the Botanic Gardens and Eastern Park. There are 36 trees listed on the Significant Tree register that are being supported through the drought with supplementary watering.
The Geelong Botanic Gardens Nursery and the Friends of Geelong Botanic Nursery are both exempt from all Water Restrictions. Strict management and use of water is maintained in these areas at all times.
Water Application in the Gardens
How the water is applied does vary from site to site depending on the individual plant requirements and the conditions of the exemption granted by Barwon Water.
There are two main methods:
- computer controlled irrigation system linked to a weather station
- watering with the use of a hand held hose with trigger nozzle
- drip system under some heritage trees
Alternative Water Options
Alternate water can be used but there are a number of points to consider:
- The quality of water – will it have an adverse effect on the plants or trees as well as the irrigation system both short term and long term.
- Regular water quality testing needs to be completed to ensure the water is fit for purpose. The salt level is only one of the 15 key water quality criteria to be considered for use on plant life for example.
- Treatment of alternate water to bring up to a quality that is suitable for ongoing use on plants is capital intensive.
- Is the alternate source of water sustainable – where is water to be sourced from? The Master Plan for Eastern Park and Geelong Botanic Gardens does identify the harvesting of storm water which will be explored in 2009 and 2010.
- Where will the alternate water be stored? Water needs to be available when it is required for application. In 2007/08 there was approximately 20 megalitres of water used at the Botanic Gardens. This volume would result in considerable storage being required.
- Economic viability of transporting water
- Potential OHS and public health issues with use of alternate water
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